This mod allows all NPC's in your covenant to use all of their equipment slots (though warriors and priests still cannot use capes). There are two versions, one with all of the equipment slots and one with all the slots EXCEPT jewelry, rings, and neck.

This mod could potentially unbalance the game in favor of player covenants.
If I can ever figure out how to remove only the player's NPC boosts, or allow the other covenant's NPCs to use equipment too then the balance could be better preserved.